The invention relates to fuel supply systems. More specifically, the invention relates to fuel supply systems including pressurized oxidizer.
In internal combustion engines fuel is mixed with air and the mixture is burned in a combustion chamber to drive the engine. It is known in the art that engine output can be enhanced by decreasing the fuel-to-oxygen ratio. In automotive applications, this is often accomplished by adding pressurized oxidizer to the fuel prior to combustion.
Prior art fuel supply systems of this type include a fuel pump that pumps fuel from a fuel tank or reservoir to a mixing chamber (e.g., intake manifold), and a depletable containment vessel containing pressurized oxidizer (typically a pressurized oxygen gas mixture) that expels oxidizer into the mixing chamber. Fuel is delivered to the mixing chamber at a rate determined by a fuel pressure regulator that is not referenced to the oxidizer pressure and that is in communication between the fuel pump and mixing chamber.
One problem with such prior art fuel supply systems is the variable nature of the pressurized oxidizer. Pressure in the containment vessel may vary with ambient temperatures surrounding the vessel, and with the volume of oxidizer contained therein. As a general rule, a decrease in ambient temperature or volume of oxidizer in the containment vessel will result in decreased oxidizer pressure, and an increase in ambient temperature will result in an increase in oxidizer pressure. Because fuel is provided at a substantially constant pressure and rate, changes in the amount of oxidizer provided alters the fuel-to-oxidizer ratio. As a result, the engine may stumble and stall if the fuel-to-oxidizer ratio becomes too high, or the fuel may bum too fast and damage the engine if the fuel-to-oxidizer ratio becomes too low.
Some prior art fuel supply systems utilize a bottle heater to maintain a desired temperature in the containment vessel, and thereby negate the effect of ambient temperature fluctuations. These systems do not address the problem of oxidizer depletion within the containment vessel, however. Additionally, bottle heaters can cause problems relating to overheating the oxidizer which can lead to engine damage or rupture of the containment vessel.
The present invention provides a fuel supply system including a source of oxidizer, a source of fuel, and a fuel pressure regulator that is referenced to the oxidizer pressure. Preferably, the source of oxidizer is a containment vessel containing a pressurized oxidizer such as oxygen, nitrous oxide, or propylene oxide. Preferably, the source of fuel is a fuel pump for pumping gasoline or another fuel.
The fuel pressure regulator includes a first surface area and a second surface area. The pressure in the source of oxidizer acts on the first surface area, which is provided by a first pressure member (e.g., a piston), and is transformed into a first force proportional to the first surface area. The first force then acts on a second pressure member, which is preferably a flexible pressure member (e.g., a diaphragm).
The source of fuel pressurizes the fuel in a pressure chamber to which the second surface area, which is preferably provided by the second pressure member, is exposed. The fuel pressure is thus transformed into a second force proportional to the second surface area. When the second force exceeds the first force, the second pressure member moves (e.g., deflects or flexes), actuating a bypass valve to route excess fuel back to the fuel pump, thereby determining the maximum resultant fuel pressure. Alternatively, the fuel pressure regulator may be a returnless or non-bypass regulator that modifies the flow of fuel into the pressure chamber.
Alternatively, a joining member (e.g., a lever arm) may extend between the first and second pressure members. The first and second forces create first and second moment forces, respectively, on the joining member. When the second moment force exceeds the first moment force, the second pressure member moves, actuating the bypass valve and thereby determining the maximum resultant fuel pressure. A fulcrum is positioned at a point along the joining member. The position of the fulcrum may be adjusted to modify the required second moment force.